1. Field of the Invention
The present invention relates to a substantially emulsifier-free aqueous cosmetic or dermatological preparation comprising at least about 13% by weight of microcrystalline wax and a ratio of lipophilic to lipophobic perfume ingredients of from about 0.5:1 to about 4:1. The preparation is suitable for application on wet skin and thus permits use while showering and imparts a scent-sensory impression both during use under the shower and also after it which has a long-lasting effect and can be readily perceived by the consumer.
2. Discussion of Background Information
Cosmetic or dermatological preparations can be divided on the basis of their application time and their application purpose. Some products are immediately washed off after use (“rinse-off”), others are intended to remain for longer on the skin and are effective there (“leave-on”).
Cosmetic preparations for skin care are primarily developed for use on dry skin. This form of preparations are known as leave-on preparations, such as creams, lotions or body milk. Often, these are formulated as emulsions, in particular W/O, O/W, O/W/O or W/O/W emulsions.
Emulsions are generally understood as meaning heterogeneous systems which comprise two liquids that are immiscible or only miscible to a limited extent and which are usually referred to as phases. In an emulsion, one of the two liquids is dispersed in the form of very fine droplets in the other liquid. The liquids (pure or as solutions) are present in an emulsion in a more or less fine distribution which is generally stable only to a limited extent.
If the two liquids are water and oil and oil droplets are present in finely dispersed form in water, then this is an oil-in-water emulsion (O/W emulsion, e.g. milk). The basic character, for example electrical conductivity, sensory properties, ability of the continuous phase to stain, of an O/W emulsion is defined by the water. In the case of a water-in-oil emulsion (W/O emulsion, e.g. butter), the principle is reversed, with the basic character being determined here by the oil.
Leave-on preparations are not suitable for use on wet or moist skin. Due to the emulsifiers present, they are able to emulsify water and, due to the lipids, optionally leave behind an oily film.
By contrast, rinse-off preparations are designed for use under the shower or while bathing.
A long-term scent impression with prior art preparations can likewise be imparted only by two different products which are applied in succession. In order to experience scent impressions while showering, the user is directed to, for example, perfumed shower gels, although the scent impression of these is lost after showering. Afterwards, the user only achieves a long-lasting scent impression by virtue of perfumed cream and/or perfume.
Many cosmetic series therefore include several products with the same perfume which are to be applied in succession, such as shower gels, deodorant preparations and/or Eau de Toilette.
By contrast, rinse-off preparations involve the care aspect, as is obtained upon rubbing cream in, to a lesser extent.
It is desirable to provide a preparation which imparts a scent impression both while showering and also afterwards, without applying a second product.
One property of cosmetic products that is very important to the consumer but can only be measured quantitatively with difficulty is their texture and sensorics. The term “texture” is understood as meaning those properties of a cosmetic which can be attributed to the constitution of the preparation, perceived by a sense of feel and touch and optionally expressed in terms of mechanical or rheological flow properties. The texture can be tested in particular by means of sensorics. The texture of cosmetic products, which can optionally be influenced with the help of additives, is of virtually equal importance for the consumer as their effects which can be established objectively.
The term “sensorics” refers to the scientific discipline which deals with evaluating cosmetic preparations on the basis of sensory impressions. The sensory assessment of a cosmetic is made by reference to the visual, olfactory and haptic impression.                Visual impressions: all features that can be perceived by the eye (color, shape, structure).        Olfactory impressions: all scent impressions that can be perceived upon breathing in air through the nose, which can often be differentiated into initial odor (top note), main scent (heart note, body) and after-scent (fond note, base note). Top note, heart note and base note together form the total odor impression of the perfume. The volatile substances only released upon use also contribute to the olfactory impression.        Haptic impressions: all sensations of the sense of touch, which relates primarily to constitution and consistency of the product.        
The sensory analysis makes use of the possibility of ascertaining the overall sensory impression of a product integrally. Disadvantages of sensory analysis are the subjectivity of the impression, the ease with which the test subjects can be influenced and the considerable scattering of the results caused as a consequence. These weaknesses are nowadays countered by using groups of trained test subjects, mutual shielding of the testers, and statistical evaluation of the mostly extensive analytical data.
In view of the foregoing, it was an object of the present invention to provide preparations which besides the criteria customary for cosmetics, such as compatibility, storage stability and the like, also offer essential, hitherto unknown cosmetic benefits for the consumer. In particular the sought preparations should be suitable for a use in the body care sector, i.e. for application to the entire body and at the same time be sensorily and especially olfactory attractive.
In principle, the known different application forms, such as shampoo, shower bath, shower gel, deodorant, antiperspirant, leave-on preparations, place different requirements on the perfuming. In the case of a shower bath, the perfume has to smell pleasant under the shower, i.e., at temperatures of up to about 40° C. The temperature stability and evaporation of the perfume ingredients lead to limited selection options. Here, the impact from the mass is the main aim. The particularly long adherence of the scent beyond the showering process was hitherto not required and/or not easily adjustable. This is the case especially since hydrophilic/lipophobic perfume ingredients are rapidly rinsed off with the water and optionally surfactants. In order to achieve a prolonged scent effect, lipophilic perfume ingredients, such as essential oils, would have to be incorporated which are not so rapidly washed off. As is known, however, the lipophilic substances lead to instabilities of the overall preparations since they shift the ratio of emulsifier to lipids and therefore often bring about an oil separation.
Another object of the present invention therefore was to provide a stable product which does not require the presence of emulsifiers therein. This was particularly difficult in view of the fact that the perfumes employed contain a high percentage of lipophilic components (e.g., more than 30% by weight).
By contrast, in the case of leave-on products with long-lasting scent impression, the challenges faced are quite different. According to experience, particular attention is placed on base note and fond note perfuming to lengthen the scent impression.
The perfume ingredients have to emphasize the cosmetic, caring character of the leave-on product. Here, a prolonged endurance of the perfume ingredients on the skin is obligatory and desired.
It also is an object of the present invention to satisfy the various challenges that are imposed on rinse-off and leave-on products.